Mike's PCjr Page

Cool, thanks for going through the trouble, Alan.

Chuckphd53 - did you ever put together any of these?

I would definitely do this mod and buy a board, a neat, clean, small board whose behavior can be changed from canonical PCjr. to Tandy and back with a flip of a switch.

I am happy to pick up the mantle on these boards..

This would be Alans call of course..''

chuck

if there is enough interest I will do a board layout and get some made...

I'll document the project on my site this week and update the link here when finished. I have some boards made already + some quantity of parts. I can send what I have to anyone willing to take up the effort. They are SMT however with a TSSOP-20 (16v8), by-pass cap (0603) and a single dip-switch. The 16v8 needs to be pre-programmed before mounting and I plan on keeping my socket adapter.

The other difficult thing about the replacement is the existing DIP has to be de-soldered. Even with a descent sucker, it's a bit of a pain to take the original chip out ('157 as I recall) and replace it with a socket for either the mod (switchable) or the original '157. So I have a stick of replacement chips I had planned on sending with the boards so people could a) just cut the original chip out and desolder individual pins, and b) have a genuine replacement for reverting to original condition (+socket). Would be nice to provide a kit that has a socket, '157, and the new populated board all together.

-A

Anything I can do for the group let me know....

I don't have a way to program PALs, but 0603/TSSOP are not a problem for me. Same with desoldering the existing chip.

From what I can tell, PAL programmers are not hard to build. Alternatively, maybe we can redesign this using small SMT 74 series logic to make it easier to assemble (not requiring programming).

Alanh or Chuckphd53: Do you have any Tandy mod boards to sell? Alternatively, do you have a programmed PLD to sell? I can get the boards easily enough from OshPark, but don't have a way to program the PLD.

Thanks!
Jason

send me an email pcjr@terradock.com I can help